High entropy materials for catalysis: A critical review of fundamental concepts and applications

High entropy materials (HEMs) have attracted significant attention in catalysis due to their adjustable constituents, unique electronic configurations, abundant active sites as well as entropy stabilization. This review provides a comprehensive overview of recent advancements in HEMs, encompassing typical synthesis methods, intrinsic properties, characterization techniques, and catalytic applications in environmental governance, energy conversion, and energy storage. Moreover, the review delves into the principles underlying HEMs, including their precise definition, key characteristics, and the high entropy effects they exhibit. Notably, the various synthetic methods and high entropy effects of HEMs are categorized to emphasize the relationship between multiple compositions, structures, high effects, and the enhancement of catalytic performance in HEMs. Lastly, the review presents the prospects and challenges, shedding light on the future directions for the further development of HEMs.